The growth of hydrocarbon prices and the inevitable depletion of light oil resources have recently caused increasing attention to development of heavy oil and asphaltic bitumen deposits. Among the existing methods of developing high viscosity hydrocarbon deposits (e.g., mining, solvent injection etc.), thermal methods (hot water injection, thermal-steam well treatment, thermal-steam formation treatment etc.) are known for their high oil recovery and withdrawal rate.
A thermal-steam gravity treatment method (SAGD) is known which is currently one of the most efficient heavy oil and asphaltic bitumen deposit development methods (Butler R., “Horizontal Wells for the Recovery of Oil, Gas and Bitumen,” Calgary: Petroleum Society of Canadian Institute of Mining, Metallurgy and Petroleum, 1994: pp. 171-194.). This method creates a high-temperature ‘steam chamber’ in the formation by injecting steam into the top horizontal well and recovering oil from the bottom well. In spite of its worldwide use, this deposit development method requires further improvement, i.e., by increasing the oil-to-steam ratio and providing steam chamber development control.
One way to increase the efficiency of SAGD is process control and adjustment based on permanent temperature monitoring. This is achieved by installing distributed temperature measurement systems in the wells. One of the main problems related to thermal development methods (e.g., steam assisted gravity drainage) is steam (hot water, steam/gas mixture) breakthrough towards the production well via highly permeable interlayers. This greatly reduces the heat carrier usage efficiency and causes possible loss of downhole equipment. Steam breakthrough response requires repair-and-renewal operations that in turn cause loss of time and possible halting of the project. This problem is especially important for the steam assisted gravity development method due to the small distances (5-10 m) between the production and the injection wells.
A method of active temperature measurements of running wells is known (RU 2194160). The known invention relates to the geophysical study of running wells and can be used for the determination of annulus fluid flow intervals. The technical result of the known invention is increasing the authenticity and uniqueness of well and annulus fluid flow determination. This is achieved by performing temperature vs. time measurements and comparing the resultant temperature vs. time profiles during well operation. The temperature vs. time profiles are recorded before and after short-term local heating of the casing string within the presumed fluid flow interval. Fluid flow parameters are determined from temperature growth rate.
A method of determining the permeability profile of geological areas is known (RU 2045082). The method comprises creating a pressure pulse in the injection well and performing differential acoustic logging and temperature measurements in several measurement wells. Temperature is measured with centered and non-centered gages. The resultant functions are used to make a judgment on the permeability inhomogeneity of the string/cement sheath/formation/well system, and thermometer readings are used to determine the permeability vector direction. Disadvantages of this method are as follows:                only generalized integral assessment of geological area permeability is possible;        additional multiple measurements (acoustic logging) in several wells are necessary;        the method is not suitable for the characterization of high viscosity oil and bitumen saturated rocks.        